The use of rechargeable lithium-ion batteries is growing steadily for many applications including its use in electric vehicles (EV) and Plug-in Hybrid Electric Vehicles (PHEV). Lithium-ion batteries are also being used for electrical grid network energy storage and many other larger scale applications. Rechargeable lithium-ion batteries are already the dominant battery for mobile devices such as cell phones and computers. The method of this invention will mitigate a potential for scarcity of these battery materials.
As these batteries reach their end-of-life, there is a need to provide a satisfactory recycling and disposal procedure for them. This is particularly accurate for the large size prismatic batteries which are made for automotive and grid-storage applications. These large format batteries, and their respective cells, contain anodes which may comprise carbon coated on copper foil and cathodes which may comprise expensive lithium metal oxides such as lithium cobaltate, mixed lithium nickel/manganese oxides, lithium cobaltate/manganese/nickel oxides and related cathode materials on aluminum foil.
Currently, there are two recycling processes being used for lithium-ion batteries: 1) batteries are processed with an electric furnace already containing molten steel with the contained anode reducing carbons along with the separators and with flux to enrich the forming stainless steel alloy in cobalt, nickel and/or manganese. The lithium is fluxed into the slag and may be recovered at high cost with several extra processing steps (Umicore process, described in US20120240729 A1); and 2) batteries are processed with a hammer mill and the screened −25 mesh slurry filtered and packaged. The slurry contains about 30% metals from the cathode along with the carbon. This metal rich mixture is shipped to an electric smelter for utilization in making steels. The copper and aluminum foils are separately recovered from the process (Toxco, Inc. U.S. Pat. No. 5,345,033 and U.S. Pat. No. 5,888,463). Although the valuable cobalt and nickel is recovered along with the manganese for scrap metal prices, the full value of the lithium metal oxide cathode material is lost and usually there is no recovery of the lithium.
These processes are expensive and cumbersome and, with respect to lithium-containing recoverable materials, generate low yields of such recoverable materials. Another recycling process being used involves the roasting of lithium-ion secondary batteries, described in U.S. Patent Application No. 2013/0287621. This process is expensive, and does not recover the full value of the recoverable materials.
It would therefore be a major improvement in the recycling of battery materials if the full value of the lithium-containing recoverable materials could be achieved by complete recovery and regeneration for direct reuse in a new lithium-ion battery. In addition, almost all of the lithium would also be recovered in the cathode material and remain as part of the lithium metal oxide cathode as it is regenerated and used in the new battery. The recovery and reuse of the cathode material would lessen pressure on the supply of lithium cathode materials like nickel and cobalt.